Power-operated dogging mechanism



Jan. 23, 1934. l E, H, PERCY 1,944,286

' POWER OPERATED DOGGING MECHANISM Filed NOV. 20, .1924

mi #hun M Patented Jan. 23, 1934 POWER-OPERATED DOGGING MECHANISM Edwin H. Percy, Fort Bragg, Calif., assigner, by mesne assignments, to The Prescott Company, a corporation of Michigan Application November 20, 1924 Serial No. 750,968

19 Claims.

This invention relates to power-operated dogging mechanism for saw-mill carriages. The present application is in the nature of a part Y continuation of my prior application, Serial Num- 5. ber 684,105, filed January 3, 1924, now Patent No. 1,836,496 and has particular reference to what is termed tong dogs. Such dogs consist of a pair of dog arms mounted to swing towards and A from each other in a Vertical plane on the knee IG of a carriage, one dog engaging the top of the log and the other engaging the bottom thereof. By thus gripping the top and bottom of the log rather than the sides thereof, no injury is done to the backboard, which is the term applied. to the sawed face of the log resting against the knee. It is the principal object of this invention to provide dogs of this general type, capable of gripping the largest and smallest sized logs at their top and bottom portions, and to operate such dogs by power means.

In said prior application filed by me January 3, 1924, Serial Number 684,105, I show electrical means for operating said tong dogs wherein the motors are stopped only by the resistance of the dogs after entering the log. In practice this results in imposing such severe strains upon the motors and other parts of the mechanism as to result in early deterioration of the same. Hence, in the present application I have provided a friction device whereby the motors may continue to rotate after the dogsl have been stopped, either by the log or by the knee-frame.

One form which my invention may assume is l, exempliiied in the following description and il- 35- lustrated in the accompanying drawing, in which Fig. 1 shows a perspective View of a knee of a saw-mill carriage, equipped with power-operated clogging mechanism embodying my invention;

Fig. 2 shows a sectional view ofthe spur gear including the friction connection used in the driving mechanism;

Fig. 3 shows a side elevation of the spur gear and friction device; i Fig. 4 shows a detailed sectional view of the 5 guide for the-toothed racks employed in the driving mechanism.

The invention herein illustrated includes a head block l and a knee 1l. As in the usual sawemill carriage, the knee is slidable on the -head block, its movements being controlled by set works and taper devices which form no part of the present invention. On the knee frame is mounted a pair of dogs 12, which are termed tong dogs. The lower dog is pivotally mounted 55 on a pin 13, with a slotted connection so as to (Cl. 14S- 125) allow some endwise movement. The upper dog is pvoted on a pin 14, which is carried by a pair of swinging arms 15 connected to a pin 13. Both dogs have a lug or boss 16 working in a guide-way 17 on the knee. This guideway is vertically dis- 60 posed and is carried back at the upper end of the knee, so that the upper dog will be retracted out of the way oi the log when not in use. There is a spring or rubber bumper 18 at the upper end oi the guideway, forming aresilient stop for V the upper dog.

The lower dog has a toothed rack 19 pivotally connected to it, and this rack extends up through a bifurcated portion in the upper dog, where it meshes Vwith'a pinion 20 xed upon a shaft 21 70' journalled on said upper dog. There is a relatively large spur gear 22 on the outer end of this shaft, which meshes with a pinion 23 on the shaft of an electric motor 24, which motor is mounted upon the upper dog and swings therewith.

The rack 19 is guided and held in mesh with the pinion 20 by means of a pair of rollers 25 engaging with the rear edge of the rack and car, ried by a frame 25a, which is pivotally mounted 80 on the shaft 21. This form of guide will allow the rack to change its angular position and will at all times keep the rack in engagement with the driving pinion.

Normally the dogs are separated, the lower one resting at the bottom of the knee, and the upper one being in contact with the bumper 18 and held in this position by suitable brakes on th motor.

When the motor is set in operation it causes the upper dog to descend along the rack, and when the upper dog strikes the log the lower dog will be pulled upwardly by the rack. I pro-I vide a friction connection so that when both dogs are suiiiciently engaged with the log, the motor and spur gear 22 may continue to rotate. This friction connection is shown in detail in Figs. 2 and 3, and comprises a pair of plates 26 keyed to the shaft 21, engaging at opposite sides of the spur gear, the latter being loosely mounted on the shaft. One of these plates abuts against a shoulder on the shaft and the other plate is pressed against the spur gear by a plurality of springs 2'? coiled around pins 28 and abutting against a, plate 29 on the outer end of said shaft. 105 The tension of the springs can be varied by means of a nut 30, threaded on to the outer end ofthe shaft and working against the plate 29.

In practice there are several of these clogging I devices on a single carriage, and all motors are under control of the set-works operator. When a log is rolled onto the carriage the set-works operator closes the switch so as to set the motors in operation in a direction to sink the dogs into the log. After the dogs are sufficiently engaged with the log the motor and spur gear 22 may continue to rotate, on account of the friction connection between said spur gear and the shaft 21. This will prevent sudden jars and strains upon the motor, and the operator may cut out the motor at his leisure. Usually these motors are provided with automatic brakes, so that after the dogs are engaged and the motors stopped, accidental releasing of the dogs would be prevented. When the log is to be turned or taken on, the carriage, the operator throws the switch so as to reverse the motor, and in this way the dogs are forced open. When the dogs reach the limit of movement permitted by the guideway 17, the friction connection will again come into play, and allow the motor and spur gear 22 to rotate after the dogs have ceased to move. Thus the friction connection serves both in driving the dogs into the log and releasing them, and prevents sudden shocks to the motor, and generally reduces wear and tear on the entire mechanism.

I do not conne my inventv ion to any particular form of friction connection, as it is realized that a variety of different forms may beused for this purpose, and the location of the same may also be varied. While I realize that friction connections are not new per se, it is believed that ihe use of such a connection in the particular combination here presented is novel.

It will be noted that the log is securely gripped at its top and bottom portions and that there are no spurs to come into engagement with the side of the log resting against the knee. Thereby the faces of the boards are not'marred, as is the case with the usual form of knee dogs or boss dogs. The links 15 which pivotally support the end of the upper dog and the slotted connection which receives the pivot for the lower dog, permit longitudinal or endwise shifting of the dogs independently of each other and allow them to follow the course of the guideway 17 in all positions of their movement. By having the pivoed ends of the dogs spaced a considerable distance from each other, the changes in the angularity of the dogs in moving from one extreme to the other is not so great as would be the case if the pivoted ends were not spaced apart. Thus the vertical portion of the knee can be made relatively straight and extended up to a considerable height, so as to accommodate the largest logs. By having the power means and gearing located on the upper dog the latter will be caused to engage the log before the lower dog strikes the log, inasmuch as the weight of the motor and gearing will cause the upper dog to descend and embed itself in the log before the lower dog is lifted. This action of the upper dog will cause the log to roll inwardly against the knee. On the other hand, should the lower dog be the first to engage the log or even strike it before the upper dog had rmly gripped the log, then there would be a tendency for the log to roll away from the knee, and perhaps to leave the carriage entirely.

What I claim and desire to secure by Letters Patent is:

1. In a saw-mill carriage, the combination with a knee of a power-operated dogging mechanism comprising a pair of dogs mounted to swing in a vertical plane on the knee, a toothed rack carried by one dog and extending past the other, a pinion on the latter dog engaging said rack, power-operated means for driving said pinion, and a friction connecion between said power-operated means and the pinion, whereby the power-0perated means may continue to rotate after the dog is stopped. i

2. In a saw-Inill carriage, the combination with a knee of a power-operated dogging mechanism comprising a pair of dogs mounted to swing in a vertical plane on the knee, a toothed rack carried by one of the dogs and extending past the other, a pinion on the latter dog engaging said rack, a shaft for said pinion, a gear on the shaft for driving the latter, a power-operated device for driving the gear, and a friction connection between the gear and shaft whereby the powerloperated device and the gear may continue to rotate after the dogs are stopped.

3. In a saw-mill carriage, the combination with a knee of a power-operated dogging mechanism comprising a pair of dogs mounted to swing in a vertical plane on the knee, a toothed rack pivotally mounted on one of the dogs and extending past the other, a pinion on the latter dog meshing with said rack, means for driving said pinion, and a swinging frame mounted co-aXially with said pinion and having means to engage said rack at i's rear edge-to guide the same.

4. In a saw-mill carriage, the combination with a knee of a dogging mechanism comprising a pair of dogs pivotally mounted to swing in a vertical plane on the knee, a swinging pivotal support for the upper dog, and a xed pivot for the lower dog having a slotted connection whereby said dogs are permitted io shift endwise independent of each other, and guide means to control the degree of shifting of the dogs.

5. In a saw-mill carriage, the combination with a knee of dogging mechanism comprising a pair of dogs pivotally mounted to swing in a vertical plane on the knee, reversible power-operated means for moving said dogs towards and from each olher, and a yielding buier carried by the knee to engage the upper dog at the end of its upward stroke.

6. A dogging device for saw mill carriages, said device comprising a knee frame adapted to be slidably mounted on a head block, said frame having a vertical aligning face at one end thereof, upper and lower operating arms each pivotally supported by the frame at the end thereof opposite the aligning face, means at the ends of the operating arms adjacent said alining face for engaging a log on said head block, electrical driving means for swinging said arms in opposite directions whereby the means at the ends thereof will engage the upper and lower sides of a log on the head block, said driving means comprising an electric motor supported by the upper arm, a pinion journaled on the upper arm and engageable with a rack pivotally connected at its lower end to the lower arm, and a driving connection between said motor and said pinion.

'7. In a saw mill carriage, the combination with a knee, of dogging mechanism comprising a pair of arms pivotally mounted to swing in a vertical plane on the knee and each having a spur to engage a log, one at the top and the other at the bottom, a rotatable motor mounted upon the upper arm, and gear connections between the motor and said arms whereby the latter are moved towards and from each other, the weight of said motor and driving connections causing the upper arm to be moved downwardly in advance of any upward movement by the lower arm.

8. A power sawmill dog of the tong type coinprising a knee having a face, upper and lower elongated tong members, means for pivotally supporting the rearward ends of the tong members in vertically spaced relation and at a substantial distance rearwardly of the knee face to permit them to move up and down toward and away from each other, means coacting with the forward portions of the tong members and with the knee for constraining the tong members to up and down movement toward and away from each other, and motor driven means interconnecting the tong members and operable to cause the upper tong member to move down and engage the upper side of the log and subsequently to cause the lower tong member to move up and engage the under side of the log.

9. A sawmill dog comprising upper and lower elongated tong members, means for pivotally supporting the rearward ends of the tong members on a sawmill knee, means on the knee for guiding the tong members adjacent their forward ends, a motor carried by one of the tong members, a driving member actuated by the motor and mounted on the same tong member as the motor, a power transmitting member operatively engaged with the driving member and connected with the lower tong member whereby upon operation of the motor the driving member idles along the power transmitting member until the upper tong member engages the log, the power transmitting member then being raised to lift the lower tong member into engagement with the log and both tong members being driven into the log simultaneously in the iinal phases of the operation.

l0. In a sawmill carriage, the combination with a knee having a guide way formed with a vertically extending portion and a rearwardly curving upper portion, upper and lower log engaging arms having means coacting with the guide way to constrain the arms to follow the guide way, a swinging support for the rearward end of the upper log engaging arm, and means for supporting the rearward end of the lower arm for pivotal and longitudinal shifting movement.

11. In a sawmill carriage, the combination with a knee having a face, of upper and lower elongated tongs, means coacting with the forward portions of the tongs to constrain them to movement in a vertical plane, means supporting the rearward end of the lower tong at a substantial distance rearwardly of the knee face for pivotal and longitudinal shifting movement, a swinging member supportingA the rearward end of the upper tong at a point substantially rearwardly of the knee face and vertically spaced from the point -at which the lower tong is supported and permitting pivotal and longitudinal shifting movement of the upper tong, a pinion rotatably supported on the upper arm, a reversible rotary motor mounted on the upper arm and geared to said pinion, and a rack pivotally connected to the lower arm and meshing with said pinion.

12. In a sawmill carriage, the combination with a knee having a face, of upper and lower elongated tongs, means coacting with the forward portions of said tongs to constrain them to movement in a vertical plane, means for supporting the rearward ends of tongs at a substantial distance rearwardly of the face of the knee and in vertically spaced relation to each other and for pivotal and longitudinal shifting movement, and

a reversible motor for actuating the tongs and includingtwo relatively movable parts, one connected to one of said tongs and the other connected to the other of said tongs.

13. In a sawmill carriage, the combination with a knee having a face, of upper and lower elongated tongs, means coacting with the forward portions of said tongs to constrain them to movement in a vertical plane, means for supporting the rearward ends of tongs at'a substantial distance rearwardly of the face of the knee and in vertically spaced relation to each other and for pivotal and longitudinal shifting movement, a reversible rotary moto-r supported upon one of said tongs, and power transmission mechanism actuated by said motor and interconnecting said tongs whereby to move said tongs toward each other when said motor is operated in one directio-n and to move said tongs away from each other when said motor is reversely operated.

le. In a sawmill carriage, the combination with a knee having a face, of upper and lower elongated tongs, means coacting with the forward portions of the tongs to constrain them tc movement in a vertical plane, means supporting the rearward end of the lower tong at a substantial distancerearwardly of the knee face for pivotal and longitudinal shifting movement, a swinging member supporting the rearward end of the upper tong at a point substantially rearwardly of the knee face and vertically spaced from the point at which the lower tong is supported and permitting pivotal and longitudinal shifting movement oi the upper tong and a reversible motor supported upon and having differential driving connection with said tongs so as to operate the upper tong into log engaging position and thereafter the lower tong into log engaging position and finally to drive both tongs into the log.

l5. The combination with a sawmill carriage, an upper dog therefor, a lower dog therefor, and a reversible motor for actuating the dogs, including two relatively movable parts, one connected to one of the dogs and the other connected to the other of said dogs.

16. In combination with a sawmill carriage, a pair of dogs mounted thereon and a reversible motor supported upon and differentially interconnected between said dogs whereby the power of said motor is diferentially applied to the dogs to operate one of said dogs into log engaging position and when arrested by such engagement to thereafter operate the other of said dogs into log engaging position through one continuous operation of said motor.

17. The combination with a knee of a sawmill carriage having a face, of upper and lower opposed log holding members adapted to be driven into the body of a log from above and below, means for supporting said log holding members for free vertical movement toward and away from each other and a motor supported by and interconnected with said log holding member, said motor beincr operable in one directionvto force the log holding members apart, said motor when operated in the other direction being aided by its own weight and the weight of the log holding members first to cause the upper log holding member to move downwardly until it engages the log whereupon the motor lifts the lower log holding member up into engagement with the log and nally drives both clogsl simultaneously into the log.

18. The combination with a saw mill carriage,

llfll isc 19. The combinationA with a saw mill carriage, an upper dog therefor, a lower dog therefor, and a reversible motor for actuating the dogs including a stator connected to one of the dogs and a rotor connected to the other of said dogs.

EDWIN H. PERCY. 

